Spark-plug.



A. G k A. J, BERGSTRO,

Patnted Jun@ 2, 19M.

UNIE STAT PATENT OFFICE.

ADOLPE G'. BERGSTRM ANB ARTHUR il. HERGSTROM, 0F ROCKFORD, ILLNOISI.

eenen-enne.

inocencia.

lsinon and ARTHUR J.. Bressa-noni, both citif zens ol the United States, residing at Rochford. in the county of Winnebago and State of illinois, have invented Certain ncw'and uset'ul Improvements 1n Spark-Enga, ot

which the following is a specification.

The object ot' this invention is to produce .an improved spark plug of high elliciencyv ainl'reliahility in'which the electrodes pre: sent a large surface. so that a large spark will he produced, and so that the electrodes will remain serviceable even though a. porlion of a space between them should become bridged by a deposit of burnt carbon.

ln the accompanying drawings, Figure l is a sideielevation of a spark plug,r embodying; the features of our invention, Fing. 2 is an enlarged longitudinal central section 'through the plug on line 2 2 of Fig. 3. Fig'. 3 is an 'eind elevation taken from the lower end of Fig. 1. Fig. Ll* is a section on line l 4 ot Fig. 1. Fig. 5 is a fragmentary elevation of the inner side of one of the outer electrodes. Fig. 6 is an enlarged perspective View of the lower portion oi' the central electrode'. y

The body of our spark plug may he of the usual or' any preferred construction, being herein shown as comprising' a tubular outer casing,- 1, a sleeve "2 of insulatinga material fitting therein and' held in place by means of a gland 3, and a central electrode l positioned within the sleeve 2 and having one or more nuts 5 threaded on its upper end. The lower portion of the electrode si. consists oi' a wire if, which maybe either integral with the rod fl, or formed Separately therefrom and attached thereto' iu any suitable way. lhe wire l" isbent to provide a transverse portion or cross piece l, preferably of a length slightly lees Ithan the inner diemeter of the casing l, so that the central electrode may be withdrawn upwardly through said casing. The lower end ol' the casing .l has a pair of electrodes proectingg therefrom. each or said electrodes having at its Afree end a cross-piece 7. Said cross-pieces are relatively long and the adjacent sides pecllloatlon of Lettere Patent. Application flied itcceimber d0, lilla. Serial No.?39.174.

Patented June?, 1914.

8. 'llie crosspiece el oit the inner electrode extends centrally within and longitudinally ot thisA sparkinggir space parallel with the sides of the cross-pieces T. '.lhe cross-pieces l and 7 are of substantially the same length.

vCl/hen an electric circuit is-closed through the spark plug, the current will jump Detween the inner sides of the cross-pieces? and the cross-piece 4a atv a plurality of' `lated to gire the best possibile? ignition. In"

case a deposit of oil should collect between the cross-pieces la and i", sons to bridge the space 8 at one or more pointe, the qportions of the space not bridged will continue to be serviceable, so that the spark pluiel will remain o erative. From a practical standpoint7 tiis feature is ot' very great importance. Many of the spark plugs heretofore produced have had two electrodes, having` theirends positioned close together between which ends the spark isy drawn` In such plugs, if oil collects between the adjacent ends oi the electrodes, the plug will he rendered entirely unserviccable. As will he seen, the present plug overcomes this disad- \fantage, because, even though a portion of the, sparligap should be bridged, there will still remain other portions through which the necessary spark may jump.

We claim as our invention:

.il spa-rl( plugP comprising a casing adaptL ed to be mounted in an engine cylinder, a central electrode positioned in and insulated 'from said casing, said clectrodehaving a cross-piece at its lower end,l two projections extendingl from the lower end of said cas-, ing, and a transverse, portion ,carried by the lower end of each ot' said projections, said transverse portions projecting inwardly from said projections, toward the cross piece and presenting surfaces lying at opposite sides ol said crosspiece and disposed longitudinally of and parallel with said cross-piece,

ln testimony whereof we allix our signatures inv presence of two witnesses.

W itnesscs:

lll1 .A fi. lloGmNn, ll. lli. Watson. 

